Research On Information Structures And Three-way Group Decision Method Of Covering Information Systems

Covering information systems as the generalization of information systems are important models in the field of artificial intelligence.Granular computing is a vital mathematical tool of artificial intelligence.Under the framework of granular computing,information structures in information systems have a great research significance.Three-way decision is a hot research topic in recent years and offers a new perspective for solving practical decision-making problems,which conforms to human’s cognitive pattern.This dissertation reports on exploring information structures and a three-way decision method of a covering information system,and the structure of this dissertation as follows:In chapter 1,it briefly introduces the ideological source and research status of information structures in information systems,as well as elaborates the thought and research status of three-way decision.Meanwhile,it introduces the research significance and structure of this dissertation.In chapter 2,a covering information system can be viewed as an information system that consists of multiple coverings in the universe.First of all,it structures information granules in covering information systems on the standpoint of Granular Computing,and presents the notion of information structure in a covering information system by means of set vectors.Then,on the light of information structures,it researches relationships between them from two aspects of dependence and separation.It also investigates some properties of information structures in a covering information system.Moreover,it studies invariant characterizations of covering information systems under the condition of homomorphism.In chapter 3,there exist decision attributes in a covering information system that is addressed as a covering decision information system.From the perspective of group decisionmaking,it transforms single-valued loss functions into interval loss functions,which provides a new explanation for determination of loss functions.Furthermore,based on the idea of decision-theoretic rough sets,it proposes a three-way group decision method of covering decision information systems.It gives an example of job competition to illustrate feasibility of the proposed method.